Investigation On The Co Selective Redution Of Aromatic Nitro Compounds By Thermoregulated Phase-transfer Catalysis

Aromatic amines with substituted by carbonyl, chloro-, cyano or olefinic groups are important fine chemical intermediates widely used in the dye, pigment, pharmaceutical and pesticide industries. Now the industrial synthesis of the aniines is catalogued into two kinds of reactions. One kind of reaction is the reduction of aromatic nitro compounds using iron powder, alkali metal sulfides(like Na2S), or alkali metal hydrogen sulfides as catalysts; Another is the catalytic hydrogenation of nitro compounds using Pd, and Ni etc. However, the former produces a lot of waste which is harmful to environment, the latter is lact in the selectivity toward the desired aromatic ainines . For the first time, the water-soluble ruthenium-carbonyl catalysts prepared by thermoregulated phase-transfer phosphine ligands (PETPP PEODPPSA) and triphenylphosphine trisulfonate(TPPTS) with Ruj(CO)12 have been applied to CO selective reduction of aromatic nitro compounds. It was hoped that new catalysts having high catalytic activity, being easily separated and recovered from products could be found , meanwhile, reaction kinetics were studied. Chief research results were as follows: Utilizing water-soluble Ru3(CO)9(TPPTS)3 as catalyst, the effects of surfactants and its concentration, NaOH, temperature and pressure on the CO selective reduction of aromatic nitro compounds were investigated and discussed in detail. Under the conditions of 120 ~C , Pco~4MPa, CTAB (cetyltrimethylammonium bromide)=6.9 X 103mo1/L, 3MNaOH and t8br, both the conversions of o-C1C6H4NO2 and the yield of o-C1C6H.4NH2 were 99%. After reuse of the catalyst for 3 times both the conversion of o-C1C6H4NO2 and the yield of o-CIC6I-hNH2 have been retained above 90%. when the catalyst system was applied in the reaction of aromatic nitro compounds //? with substituted by C=O or -CN groups, the reduction had good activity and high selectivity too. The acceleration effect of surfactant on the reaction was discussed. For the first time, the water-soluble ruthenium-carbonyl catalysts prepared by thermoregulated phase-transfer phosphine ligand P[C6H4-p-(0C2H4)60H]3 with Ru3(CO)12 has been applied to CO selective, reduction of aromatic nitro compounds in the aqueous/organic two-phase. When this catalyst complex was applied to o-CIC6H4NO2 , p-C1C6H4NO2, p-NO2C6H4CN and o-NO2C6H4COCH3 which were selectively reduced to o-CIC6H4NH2 , p-CIC6H4NH2, p-NH2C6H4CN and o-NH2C6H4COCH3, both the conversions and the selectivity reach were 98%. CO selective reduction results of o-CIC6H4NO2 are investigated and discussed in detail. Under the conditions of 14000, Pco~4MPa and tlOhr, the conversions and yields of reaction were 99% and the selectivity as near 100%. After recycling of the catalyst for 3 times the conversion of o-C1C6H4NO2 has been retained to be above 94%. Catalytic activity prepared by four different water-soluble phosphine ligands (Ph3P(TPP), Ph2P(m-C6H4SO3Na(TPPMS), TPPTS and PETPP) with Ruj(CO),2 and the effect of Vwater/Vorganic ratio on the CO selective reduction of o-CIC6H4NO2 were investigated. The experimental results revealed that catalytic reaction occured in the organic phase, which insighted that there was a hermoregulated phase-transfer catalysis?process presented in the reactions. A novel catalyst by coordirating new thermoregulated phase-transfer phosphine ligand...